Bone drill



FIG. 1 is a top plan view of a bone drill, showing my new design;

FIG. 2 is a bottom plan view;

FIG. 3 is a side elevational;

FIG. 4 is a right end view; and,

FIG. 5 is a left end view.

The broken lines are shown for illustrative purposes only. 

The ornamental design for a bone drill, as shown and described. 